GKN Overdrive In TD5

[brianmac59@bigpond.com]

I myself have a question.

Does anybody out there have experience with the GKN R. Type Overdrive fitted, in my case to a 2003 110 Defender.

Problem: It pumps oil from the transfer box into the GKN, thus overfilling it.
Consequence: Excess oil discharges through breather pipe all over the the bell housing. This morning I did a clean up (one of many), and added 800ml of oil back into the transfer box.
It can go for 100's of Kilometers and be ok, then, for no apparent reason it spits the dummy.

When it happens I become aware of the problem when I try disengaging the OD unit, vehicle surges and does not know whether to engage or disengage.
Any ideas would be appreciated
Cheers, Brian

[TSD]

I think the only way for oil to pass from the transfer box into the GKN would be via the oil seal in the front carrier plate - worth checking, but I wouldn't expect much to get past even a duff seal. If your transfer box breather blocked or crimped shut?

Slow disengagement is usually caused by excessive oil pressure in the OD - that might be caused by EP90 from the transfer box contaminating the ATF, or by sticking relief valves or blocked bleed holes (under the three screwed caps under the oil filter screen) or sticking solenoid valve. On mine, the high pressure filter was completely blocked with aluminium dust carried in on the oil.

This is a good series of articles on the Triumph Overdrive - which is almost the same thing as the GKN one. (The O-ring sizes listed in the rebuild section are correct for the GKN one)

[reb78]

I think I've replied on another forum. Replace the sealed Orange bearing and the two oil seals on the transfer plate.

[101sean]

The orange bearing isn't a standard one unfortunately. Devon 4x4 were doing overdrive spares but TBH, the GKN OD isn't up to the job on a Defender. Gave up on mine and now have a Disco Tbox, the OD is gathering dust in the shed alongside a wrecked LT95 Fairey OD (but that's another story!)

[mmgemini]

The orange bearing isn't a standard one unfortunately. Devon 4x4 were doing overdrive spares but TBH, the GKN OD isn't up to the job on a Defender. Gave up on mine and now have a Disco Tbox, the OD is gathering dust in the shed alongside a wrecked LT95 Fairey OD (but that's another story!)

I'll second that.

I must get my knackered OD off to save some weight.